1. Field of the Invention
The invention relates in general to a sintered heat pipe, a manufacturing method thereof and a manufacturing method for a groove tube thereof, and more particularly to a sintered heat pipe with grooves, a manufacturing method thereof, and a manufacturing method for a groove tube thereof.
2. Description of the Related Art
A heat pipe, especially a sintered heat pipe, is an apparatus having the highly conductive ability. The conventional heat pipe includes a capillary structure and a metal tube. The capillary structure is in contact with the metal tube and is usually formed on an inside wall of the metal tube. A vapor channel is defined on the inside surface of the capillary structure.
As is well known in the art, one end of the heat pipe absorbs the heat from a heat source and functions as a vaporizing sector, and the other end thereof transfers the heat to a cold source so that a liquid working fluid is formed by condensing. The liquid working fluid is processed by the capillary absorption function of the capillary structure and returns to the hot junction from the cold junction. The liquid working fluid is heated and vaporized into the vaporized working fluid in the hot junction, and the vaporized working fluid flows to the cold junction through the vapor channel and then condensed into the liquid working fluid. The tube wall of the capillary structure may be formed with a plurality of grooves so that its conductive effect becomes especially good, the flow-guide effect of the working fluid is enhanced, and the conductive efficiency is thus enhanced.
In the manufacturing methods of Japanese Patent No. 3110922 (Taiwan patent application serial No. 094202974) and U.S. Pat. No. 7,316,264 (Taiwan patent application serial No. 094210450), a copper tube having a grooved inside wall is provided. The copper tube after being sectioned has a first end and a second end. The first end is firstly closed, then the copper tube is filled with the metal powders, and then the metal powders are sintered. Next, the working fluid is injected into the copper tube and the air inside the copper tube is pumped out. At last, the second end is closed.
However, the metal powders have different sizes so that the too-small metal powders fall into the grooves. In Japanese Patent No. 3110922 (Taiwan patent application serial No. 094202974), the metal powders falling into the grooves after sintering are fixed to the grooves. This forms the congestion to the liquid working fluid, which flows from the cold junction to the hot junction, and deteriorates the conductive effect of the heat pipe.
In U.S. Pat. No. 7,316,264 (Taiwan patent application serial No. 094210450), the metal powders have to be greater than the diameter of the inside groove of the wall of the groove tube. However, this patent does not mention how to achieve this object. Unless a special manufacturing method is developed, it is impossible to make all the metal powders achieve this object according the typical method.
In addition, if the width of the groove is too wide, the capillary phenomenon after sintering becomes non-obvious, and the heat dissipation effect is deteriorated.